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H-460
Electronic shift-register based cipher machine

H-460 was an electromechanical cipher machine introduced in 1970 by Crypto AG (Hagelin) in Zug (Switzerland). It was the company's first machine that used a shift-register based cryptologic. The basic machine, which still incorporated electromechanical parts, was designed in-house in Zug, whilst the cryptologic had been developed in 1966 by the US National Security Agency (NSA).

The machine is housed in a shiny grey plastic enclosure and is powered directly from the 220V AC mains. It has a full 26-button keyboard at the front and a double strip-printer at the top.

With the H-460, Crypto AG was clearly steering away from its successful mechanical pin-and-lug cipher machines, like the C-446 and CX-52, that it had sold for nearly 30 years. Development started in 1965 but as the company had virtually no experience with electronics, there was a steep learning curve. After its introduction in 1970, it was withdrawn, and then re-released in 1972.
  
H-4605

In 1977, the machine was succeeded by the fully electronic HC-500 series of machines — also known as the CRYPTOMATIC family — of which the HC-570 was the first one to appear. It was partly developed by Motorola and featured a cryptologic based on an 6800 microprocessor.

Transport case for H-4605 H-4605 in transport case H-4605 Parts stowed below the machine Unlocking the case shell (2) Parts stowed in the bottom section of the transport case Screwdrivers, brush, metal cleaning strip and spare fuses Keys
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Transport case for H-4605
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H-4605 in transport case
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H-4605
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Parts stowed below the machine
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Unlocking the case shell (2)
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Parts stowed in the bottom section of the transport case
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Screwdrivers, brush, metal cleaning strip and spare fuses
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Keys

Features
The H-460 measures 355 x 296 x 163 mm and weights 11.5 kg. It is housed in a grey plastic enclosure, and can be operated from a desktop or from within the bottom shell of the transport case. The device is enabled with the power switch at the front right. Next, the desired MODE of operation is selected with the white keys at the front right. Note that for entering the BASIC KEY – also known as the INTERNAL KEY – the key-lock at the right hand side should be engaged first.

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The machine's output (ciphertext and/or plaintext) is printed directly onto a narrow paper strip that leaves the machine at the top (to the left of the letter counter). A suitable paper roll has to be installed behind a hinged lid at the rear. When printing, the paper is automatically sliced in two halfs, that can be used to create the final telegram. If multiple copies of the output are required (and a copying machine is not available), the external PEH-72 tape reader/puncher can be used.

MODE selector
  • O
    Plaintext
  • C
    Cipher (encrypt)
  • D
    Decipher (decrypt)
  • I
    Internal key input (basic key) — 25 letters 1
  • E
    External key input (message key) — 5 letters
  1. The basic key (I) can only be entered when the keylock to the right of the keyboard (at the side panel of the machine) is engaged. This involves inserting of the key, and turning it clockwise.

Space character
As the machine does not have a spacebar, one of the 26 letters of the alphabet has been assigned as replacement for the space character. This character can not be used as part of the text. Based on the language (and the wishes of the customer) the least frequently used letter will be assigned for this. On the keyboard it is marked in red (rather than white). If the letter occurs in a text, it should be replaced by another letter, or by two other letters, for example:

  • W
    VV
    e.g. Spanish, Italian
  • X
    KS
    e.g. German
  • Z
    TS
    e.g. English
  • K
    CC
    e.g. French
History
Development of the H-460 began in 1965, at a time when Crypto AG's designs were influenced by the American NSA. It was the result of the so-called Licencing Agreement that existed between Boris Hagelin and the American CIA since 1960. 1 It made certain machines readable 2 for NSA.

There were many problems. When the machine was announced in the late 1960s, the Italian Army promptly ordered 280 units. The first 82 units were delivered in 1970 — around the time that the company – Crypto AGwas taken over by the German Bundesnachrichtendienst (BND) and the US Central Intelligence Agency (CIA). But the machines didn't work. The design was too complex and the machines were vulnerable to temperature changes and vibrations. In particular the electronic parts – i.e. the cryptologic – appeared to be unreliable. The Italians returned the entire shipment.

The German cryptographic authority – Zentralstelle für das Chiffrierwesen (ZfCh) – intervened and mounted a redesign, using the German technology giant Siemens as a consultant. With Siemens' help, Crypto AG was able to fix the H-460 to the best of its abilities, and by 1972, ZfCh 3 was confident that the machine could be released. Crypto AG then delivered the outstanding orders.

  1. Not to be confused with the so-called Gentleman's Agreement that existed between Hagelin and the NSA from approx. 1951 to 1960. It was superceeded by the Licencing Agreement with the CIA.
  2. In this context, readable means that the cryptographic algorithms could be broken by the NSA. Also known as friendly. In contrast: algorithms that are not breakable by NSA, are called unfriendly or unreadable.
  3. At the time, ZfCh was an independent German authority that worked closely together with the German intelligence service BND. In 1973, it was placed under Department IV of the BND.

Compromise   1976
Despite the fact that the ill-fated machine had been fixed and re-released in 1972, its problems haunted the company for several more years. Customers kept complaining about the mechanical stability, and there were complaints about the strength of the cryptologic. By 1976, the Italians and the Egyptians were aware of the weakness in the algorithm, and demanded an explanation.

Crypto AG's CEO Heinz Wagner managed to fend it off with his well-known charm. The machines were returned to the factory, where an improved cryptologic — unique for each customer — was fitted. The variant was denoted by a single-digit suffix to the module number, such as H-4603, H-4604 and H-4605. The strength of the cryptographic algorithm had indeed been fixed, but the machines were still redable to the NSA, albeit with a much greater cryptanalytic effort.

The image on the right shows the hand-wired crypto­logic of an H-4605, of September 1977.
  
Cryptologic interior - three PCBs

The issue with the H-460 led to friction between the owers of the company — CIA and BND — when in 1972, the American NSA flatout refused to share the details of the H-460 cryptologic with the ZfCh – the German codebreaking authority. NSA's Frank Raven did not want to share anything that predated the purchase of the company (1970) with the partner. The matter was cleared in the spring of 1973, when Raven finally allowed the H-460 to be informally discussed with the ZfCh, as long as the details of the (informal) discussions were not documented [2].

 Operation RUBICON

The cubans
It is likely that the Cubans were able to break the H-460 – or at least some of its traffic – from 1984 onwards. The details of the analysis and software for its decryption were shared with the Ministerium für Staatssicherheit (MfS, or Stasi) of the former East-Germany (DDR) in 1988 [7].



Parts
Transport and storage case H-460x cipher machine Transport and storage case Dust cover Maintenance tools Spare print head Pair of tongs for removing/replacing the print head Ink canister
Ink
5-level paper rolls Operating instructions Power and data cables PEH-72 paper tape reader/puncher
Transport case
When unused, the machine can be stowed in this transport case. It consists of two plastic shells, that are padded with a molded shock-absorbing foam. The hinged upper shell can be removed.

Inside the top lid (i.e. the upper shell) is a compartment in which the maintenance tools and spare parts are stowed. The bottom case shell has a small compartment (under the machine) that contains the dust cover, the operating instructions and the power cable.
  
Transport case for H-4605

Machine   H-460
All versions of the machine (H-4601, H-4602, etc.) have the same outer dimensions and fit snugly inside the transport case. It can be used on a table top, but can also be operated whilst seated in the bottom half of the transport case.

All that is required for operating the machine is a connection to the 110/220V AC mains and a fresh roll of paper.
  
H-4605

Physical keys
The machine has two lock, both of which accept each of the supplied keys. The lock at the right side, is used for entering the BASIC key (i.e. the internal key). It is also used – together with the lock at the rear – to get access to the interior.

In the latter case, the two black spring-loaded knobs at the sides of the machine, should be pushed towards the rear, after which the top case shell can be removed.
  
Keys

Dust cover
When the machine is permanently installed on a desktop, for example in the communications centre of an embassy, it might not be prcatical to repack it in the transport case each time after use. For such situations, the soft grey dust cover shown in the image on the right is supplied.

When unused, the dust cover is stowed with the operating instructions, in the bottom part of the transport case, under the machine.
  
Dust cover

Maintenance tools
For regular maintenance (not for repair) a set of high-quality tools was supplied, stowed in the top lid of the transport case. Present are two screwdrivers, a brush (for removing dust) and a thin metal blade that can be used for removing paper from a blocked printer.

Also present in this compartment, is a special pair of tongs for handling the print head and an canister with ink (similar to an oil can).
  
Screwdrivers, brush, metal cleaning strip and spare fuses

Spare print head
Several spare parts were supplied with the machine, such as fuses (typically in a plastic bag), spare screws and a fresh pre-inked double print head, as shown in the image on the right.

The printhead is made of porous rubber that can accumulate ink. A special tool is supplied for removing and replacing the print head. Suitable ink was supplied in a special ink canister.
  
Blue plastic container with spare print head

Print head tongs
This purpose-made pair of tongs is supplied for handling the print head. It consists of two curved tongs, one of which is hinged. The tongs can be fitted around the centre part of the print head, and should be pressed together when removing or replacing it.

When unused, it is stowed in the tools compart­ment inside the top lid of the storage case.
  
Tool for removing the print head

Ink canister
Suitable ink for the print head, was supplied in the special ink canister shown in the image on the right. It is similar to a regular oil can, but contains ink instead of oil.

If the printed image becomes faded, the print head should be removed and ink should be applied to the black circumference with the embossed letters, which is made of porous rubber. Only approved ink should be used.
  
Ink canister

Blank paper
The machine has a double printer that produces two rows of letters: the plain­text and the cipher­text. It accepts a paper roll with a width of 17.46 mm (11/16") — the same width as standard five-level teleprinter tape (telex).

Note however, that the core is much smaller than that of a regular telex paper tape.
  
Paper rolls (17.46 mm)

Operating instructions
An A5-sized booklet with a blue cover was supplied with each machine. It contains the operating instructions in five languages: Italian, Spanish, English, French and German.

At the back of the booklet are fold-outs with drawings and photographs. The complete manual can be downloaded below.

 Download H-4605 manual
 Download PEH-72 manual
  
Operating instructions

Cables
A regular power cable is supplied, with a 3-pin female euro plug at one end. The other end is stripped, but no plug is mounted. This allows the user to fit a suitable one for the local wall sockets (which are different in most countries).

If the PEH-72 tape puncher (see below) is also present, an extra power cable is needed, plus a special data cable to link it to the H-460x. The latter is shown in the image on the right.
  
Data cable (for PEH-72)

Tape reader/puncher   PEH-72
The PEH-72 tape reader/puncher shown here, was available as an option. It can be connected to the data socket at the rear of the H-460x, and allows a decoded to text to be stored on paper tape, so that multiple copies can be printed on a regular teleprinter machine. 1

The device can also be used as a tape reader, in which case a pre-recorded ciphertext message (for example received on a teleprinter) can be read as if it was typed on the keyboard.
  
PEH-72 tape puncher

  1. In the 1960s and 70s, up to 10 copies of a (decoded) message were generally needed, whilst – for security reasons – a copying machine was not available in an embassy's communications centre.

Transport case for H-4605 H-4605 in transport case Parts stowed below the machine Tools and spare parts stowed in the case lid Tools and spare parts Keys Keys Screwdrivers, brush, metal cleaning strip and spare fuses
Tool for removing the print head Spare print head in plastic container Blue plastic container with spare print head Print head Print head Ink canister Paper rolls (17.46 mm) Dust cover
Inside the dust cover Instruction manual Operating instructions Power cord Data cable (for PEH-72) PEH-72 tape puncher with data cable PEH-72 tape puncher PEH-72 tape puncher
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Transport case for H-4605
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H-4605 in transport case
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Parts stowed below the machine
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Tools and spare parts stowed in the case lid
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Tools and spare parts
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Keys
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Keys
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Screwdrivers, brush, metal cleaning strip and spare fuses
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Tool for removing the print head
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Spare print head in plastic container
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Blue plastic container with spare print head
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Print head
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Print head
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Ink canister
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Paper rolls (17.46 mm)
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Dust cover
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Inside the dust cover
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Instruction manual
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Operating instructions
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Power cord
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Data cable (for PEH-72)
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PEH-72 tape puncher with data cable
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PEH-72 tape puncher
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PEH-72 tape puncher




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Interior
The machine is housed in a grey plastic enclosure that consists of two shells: a bottom one – that holds the internal parts – and an upper one, that can be removed by releasing two locks (one at the right and one at the rear), and pushing two black knobs (one at either side) towards the rear.

The upper case shell can now be taken away, revealing the interior of the machine, as shown in the image on the right. The machine roughly consists of three sections: the keyboard at the front, a double paper strip printer at the left, and the secret electronic cryptologic unit at the right.

Behind the printer is an electromotor that drives the mechanical parts, and – towards the centre of the machine – the mains power transformer. The shiny grey cilinder below the front of the keyboard, is an electrolytic capacitor. With the transformer and a circuit board, it forms the PSU.
  
Interior seen from the front right (cryptologic closed)

The double printer is driven by the electromotor, via a set of gears at the left side. Each unit can be stepped individually, and rotates one half of the double print head at the centre. Inside the mechanism is a rotating knife that cuts the paper strip in two seperable halfs whilst printing.

The rectangular metal box at the rear right of the machine, contains the electronic circuits, which includes the shift-register based crypto­logic — the part that contains the cryptographic algorithm. It was designed in 1966 1 by the NSA.

The metal box can be opened by removing two screws (one at the front and one at the rear) and lifting off the lid. In the original version of the H-460 that was released in 1970 2 it contained five printed circuit board (PCBs), numbered 1 thru 5. Each board represented the electronic equivalent of a single cipher wheel from the mechanical era.
  
Cryptologic interior - three PCBs

The design with the five PCBs, that was partly electronic and partly mechanical, appeared to be too vulnerable to shock and temperature variations and caused all machines to be returned to the factory. In 1972, the machine was re-released with a redesigned cryptologic, made by Siemens.

The new design consisted of three PCBs that were plugged into a motherboard at the bottom: a driver board, a digital board and a board with the cryptologic. All boards are built with CMOS integrated circuits (ICs) of the 4000-series [4].

Like the previous design, it was based on shift-register technology, designed by the US National Security Agency (NSA), but without moving parts. A standard 9V battery was used to retain the cryptographic key. It is housed in a transparent plastic holder that it fitted to the motherboard. The 9V battery should be replaced once a year.
  
Driver board

In 1976, the Italians and the Egyptians discovered the (exploitable) weakness in the encryption algorithm, and started complaining to Crypto AG. All machines were returned to the factory, and were retrofitted with an updated cryptologic that had been designed by Dave Frasier at the NSA.

Although the new algorithm was stronger, it was still readable by NSA (albeit with greater effort). The cryptologic update was released in 1977, and each country received an individual unique variant, denoted by an extension to the model number (e.g. H-4601). This made it impossible to decrypt the traffic of a neighbouring country.

The image on the right shows a close-up of the cryptologic board of the H-4605 machine in our collection. Each board is completely hand-wired with a complicated – difficult to trace – maze of insulated copper wires, similar to a spider web.
  
EPROM on cryptologic board, marked September 1977

Although the shift-register logic was state-of-the-art when it was produced in the 1970s, there are several flaws in the design. Although the hand-routed wiring was probably needed to allow for individual variations, fault finding must have been a nightmare. More importantly, the design completely lacks decoupling capacitors near the power lines of each individual integrated circuit.

  1. As part of the Licencing Agreement between the CIA and Crypto AG.
  2. Around this time, Crypto AG was purchased by the German BND and the American CIA.

Unlocking the case shell (1) and enabling entry of the BASIC key Unlocking the case shell (2) Paper feed compartment (open) Interior seen from rear left corner Interior seen from the front right (cryptologic closed) Interior seen from the rear Double printer Double printer seen from the left
Metal box with cryptologic Printed paper strip close-up - note the slit at the centre Printer driving gear H-4605 Interior, with open cryptologic unit Cryptologic interior - three PCBs Cryptologic interior Driver board Digital board
Digital board Digital board - bottom view Cryptologic board Cryptologic board - bottom view EPROM on cryptologic board, marked September 1977 Cryptologic board Cryptologic board - close-up Cryptologic board detail
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Unlocking the case shell (1) and enabling entry of the BASIC key
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Unlocking the case shell (2)
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Paper feed compartment (open)
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Interior seen from rear left corner
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Interior seen from the front right (cryptologic closed)
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Interior seen from the rear
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Double printer
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Double printer seen from the left
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Metal box with cryptologic
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Printed paper strip close-up - note the slit at the centre
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Printer driving gear
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H-4605 Interior, with open cryptologic unit
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Cryptologic interior - three PCBs
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Cryptologic interior
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Driver board
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Digital board
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Digital board
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Digital board - bottom view
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Cryptologic board
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Cryptologic board - bottom view
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EPROM on cryptologic board, marked September 1977
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Cryptologic board
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Cryptologic board - close-up
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Cryptologic board detail

Cryptologic board



Help required
Please help us to expand this page. We are currently looking for technical documentation, circuit diagrams and in particular a detailed description of the cryptologic of any version of the H-460x. If you are able to help any way, please contact us.


Specifications
  • Basic key
    25 letters
  • Message key
    5 letters
  • Power
    110/220V AC mains +15%/-10% (selector), 50 Hz
  • Dimensions
    355 × 296 × 163 mm (case: 400 × 370 × 230 mm)
  • Weight
    11.5 kg (with case: 16 kg)
Accessories
Documentation
  1. H-4605 Operating instructions (5 langauges)
    .358-c. Crypto AG, 1977.

  2. PEH-72 Operating instructions (5 langauges)
    .372-b. Crypto AG.
References
  1. Crypto Museum, The Gentleman's Agreement
    30 July 2015.

  2. Crypto Museum, Operation RUBICON
    February 2020.

  3. Chiffriertechnik Heute
    Vorlesung Krieg im Aether 1976/1977, ETH Zürich. 1
    Lecture (German). Oskar Stüzinger, 1977. pp.20-22.

  4. Wikipedia, List of 4000-series integrated circuits
    Retrieved January 2020.

  5. Klaus Kopacz, PEH-72 Operating Instructions - THANKS !
    Received January 2020.

  6. Bundesbeauftragte für die Stasi-Unterlagen (BStU) 2
    Federal Commissioner for the Stasi-Records.

  7. MfS, Mahjor Carlos Portella Hernándes (Cuba) to Generalmajor Birke (DDR)
    Analysis of the H-460 (German, translated from Spanish).
    Stasi, Abteilung X. Nr. 319. 21 July 1988. 3
  1. Retrieved from HAMFU History, December 2018.
  2. Full name: Bundesbeauftragte für die Unterlagen des Staatssicherheitsdienstes der ehemaligen Deutschen Demokratischen Republik (DDR) — Federal Commissioner for the Records of the State Security Service of the former German Democratic Republic (GDR) — officially abbreviated to BStU.
  3. Document obtained from BStU [6] and kindly supplied by Jörg Drobick.

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Crypto Museum. Created: Sunday 15 December 2019. Last changed: Friday, 08 May 2020 - 20:24 CET.
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